JPH07294066A - Refrigeration system - Google Patents

Abstract

PURPOSE:To improve durability of a compressor by providing in a passage for refrigerant composed of halogenated hydrocarbon compounds a drier charged with a desiccant composed of synthetic zeolite and an acid removing device, thereby removing inorganic acid in a refrigeration system to prevent the synthetic zeolite from being crushed. CONSTITUTION:Refigerant compressed at a compressor 11 is delivered through a condenser 14 and a drier 15, and the pressure thereof is reduced in a capillary tube 18 and then is fed into an evaporator 19 to evaporate it, thereby generating cold air. The evaporated refrigerant is returned to the compressor 11 via an accumulator 20. In such a refigeration system, desiccants 16 comprising spherically formed synthetic zeolite are charged into the drier 15. An acid removing device 2 charged with adsorbents 3 prepared by forming alkaline activated alumina into spherical bodies, 5mm in diameter, is provided downstream of the accumulator 20, where an inorganic acid contained in the refrigerant is removed, whereby degradation and crushing of synthetic zeolite constituting the desiccants 16 can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating system used for a refrigerating machine, an air conditioner or the like.

[0002]

2. Description of the Related Art In recent years, as the performance of refrigerating and refrigerating systems and air conditioners has become higher and their capacities have become higher, the load on the compressor has become more severe, and therefore, improvement in the durability of the compressor has been desired.

On the other hand, due to environmental problems such as ozone depletion and other environmental problems, the molecules such as difluorodichloromethane (hereinafter referred to as R12) and difluorochloromethane (hereinafter referred to as R22), which contain chlorine in the molecule, are used in the molecule. A change to a chlorine-free refrigerant 1, 1, 1, 2 tetrafluoroethane (hereinafter referred to as R134a) is under consideration. However, the R134a, which does not contain chlorine in its molecule, has poor lubrication performance and is in a more severe environment for the compressor.

An example of a conventional refrigeration system will be described with reference to the drawings. FIG. 3 shows a conventional refrigerant R1.
An outline of a refrigeration system using No. 2 will be described. 10 is a refrigeration system. Reference numeral 11 denotes a compressor, and the compressor discharge unit 1
The refrigerant discharged from 3 is condensed in the condenser 14.

Water is removed from the condensed refrigerant by the dryer 15. The dryer 15 is made of synthetic zeolite with a diameter of 5 m.
A desiccant 16 formed in a spherical shape of m is enclosed.

The synthetic zeolite used in the desiccant 16 is an A-type synthetic zeolite having an effective diameter of 0.4 nm that does not adsorb the refrigerant R12 having a molecular diameter of about 0.5 nm. Moisture in the refrigerant causes clogging due to freezing, so it must be strictly removed. As a desiccant for general use, synthetic zeolite, silica gel, and activated alumina are used. Silica gel and activated alumina have low water adsorption capacity,
It is not suitable for use in drying refrigerant in refrigeration systems.

Reference numeral 17 is a solenoid valve using a solenoid, and the refrigerant passes through the capillary tube 18 while being decompressed, and is evaporated by the evaporator 19. Reference numeral 20 is an accumulator that adjusts an appropriate amount of refrigerant. The refrigerant passes through the check valve 22 and returns from the compressor suction portion 23 to the compressor. By repeating this, cooling is performed.

[0008]

However, in the above refrigeration system, as a result of the decomposition of the refrigerant in the compressor at high temperature to generate inorganic acids (hydrochloric acid, hydrofluoric acid), the synthetic zeolite used as a desiccant deteriorates. The problem of crushing occurs.

That is, the conventionally used synthetic zeolite has a structure in which a part of silicon in the silicic acid anhydride is replaced with aluminum. Therefore, although it has excellent moisture adsorption and little strength deterioration during moisture absorption, aluminum easily elutes with respect to the inorganic acid, and the strength of the crystal is significantly reduced,
It is crushed by vibration of the compressor. When the load on the compressor is small, no significant problems occur.However, when the load on the compressor becomes severe, the refrigerant decomposes due to temperature rise and wear of the compressor, and inorganic acids (hydrochloric acid, hydrofluoric acid) are generated. The above problem occurs.

When the synthetic zeolite is crushed, the crushed powder circulates in the refrigeration system according to the flow of the refrigerant and enters the inside of the compressor. At this time, crushed powder of synthetic zeolite intervenes on the sliding surface inside the compressor, which causes abnormal wear.

Therefore, there is a demand for a refrigeration system that does not cause pulverization of synthetic zeolite even under a severe load on the compressor.

In view of the above problems, the present invention is to improve the durability of a compressor by removing inorganic acids (hydrochloric acid, hydrofluoric acid) in a refrigeration system to prevent crushing of synthetic zeolite.

[0013]

In order to solve the above-mentioned problems, the refrigerating system of the present invention has an adsorbent made of alkaline activated alumina as an acid removing device, which is arranged in the flow path of the refrigerant.

Further, chromium is used in an amount of 10 to 5 as an acid removing device.
An adsorbent made of a metal foam containing 0% by weight is arranged in the flow path of the refrigerant.

[0015]

According to the present invention, when the load of the compressor becomes severe and the refrigerant is decomposed, the generated inorganic acid is adsorbed on the activated alumina to prevent the synthetic zeolite from deteriorating and to improve the durability of the compressor. It will improve.

In general, activated alumina is a product obtained by heating and dehydrating aluminum hydroxide and is used as an acid adsorbent strongly against inorganic acids. However, activated alumina is a solid acid having a pH of about 6 and has an action of accelerating the polymerization of unsaturated substances generated in the refrigeration system. Therefore, it cannot be applied to the refrigeration system as it is.

Therefore, by using activated alumina whose surface is modified to be alkaline by blending sodium oxide or the like,
This problem can be solved.

Further, according to the present invention, when the load of the compressor becomes strict and the refrigerant decomposes to generate an inorganic acid, the present invention allows the metal foam containing 10 to 50% by weight of chromium to adsorb the inorganic acid. The deterioration of the synthetic zeolite is prevented and the durability of the compressor is improved.

Metals having a large specific surface area such as metal powder like activated alumina are generally used as an adsorbent for chemically adsorbing an inorganic acid. However, some acids do not have adsorptive activity depending on the type of acid generated, and it is necessary to optimize the composition.

Therefore, as a result of examining the activity against the inorganic acid (hydrochloric acid, hydrofluoric acid) generated as a decomposition product of the refrigerant, the most active metal foam containing chromium was selected. Also, the shape of the metal used as an adsorbent is excellent in powder and sintered body with a large specific surface area, but if it flows into the refrigeration system piping, it will cause clogging of the piping and wear of the compressor, so the surface hardness A metal foam that is high and generates little powder is considered to be good. Also in this respect, metal foams are superior to activated alumina.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. An outline of a refrigeration system using the refrigerant R12 of the present invention will be described with reference to FIG. 1 is a refrigeration system. Reference numeral 11 denotes a compressor, and the refrigerant discharged from the compressor discharge part 13 is condensed in the condenser 14.

Moisture is removed from the condensed refrigerant by the dryer 15. 5m diameter synthetic zeolite in the dryer 15
A desiccant 16 formed in a spherical shape of m is enclosed.

The synthetic zeolite used for the desiccant 16 is an A-type synthetic zeolite having an effective diameter of 0.4 nm that does not adsorb the refrigerant R12 having a molecular diameter of about 0.5 nm.

Reference numeral 17 is an electromagnetic valve using a solenoid, and the refrigerant passes through the capillary tube 18 while being decompressed, and is evaporated by the evaporator 19. Reference numeral 20 is an accumulator that adjusts an appropriate amount of refrigerant.

Reference numeral 2 denotes an acid removing device, which encloses an adsorbent 3 formed by molding alkaline activated alumina into a spherical shape having a diameter of 5 mm. Here, by removing the inorganic acid contained in the refrigerant, deterioration and pulverization of the synthetic zeolite used in the desiccant 16 are prevented.

The refrigerant passes through the check valve 22 and returns from the compressor suction portion 23 to the compressor. By repeating this, cooling is performed.

The characteristics of the activated alumina used for the adsorbent 3 are as follows. The composition excluding adsorbed water content is 88% by weight of aluminum oxide (AL2O3), 9% by weight of silicon oxide (SiO2), and sodium oxide (NaO2) 3.
% By weight, indicating alkalinity of solid surface at pH 8.2. Therefore, it is inert to the polymerization of unsaturated compounds present in the refrigeration system 1 and can be used without problems.

The average diameter of the pores is about 8 nm. Since the molecular diameter of the refrigerant is sufficiently larger than about 0.5 nm, there is no influence of the adsorption of the refrigerant molecules. Further, compared to the synthetic zeolite used for the desiccant 16, since the water adsorption capacity is low, most of the water is adsorbed only on the synthetic zeolite in this refrigeration system, and the amount of water in the refrigerant is strictly the same as in the conventional case. To be removed.

As described above, according to this embodiment, the pH value is 8.
By arranging an acid removal device that encloses an adsorbent consisting of activated alumina with an average pore size of about 2 nm that has an alkalinity of 2, the effects of polymerization of unsaturated compounds and adsorption of refrigerant molecules present in the refrigeration system Without it, it is possible to prevent deterioration and crushing of the synthetic zeolite installed in the refrigeration system to remove the water in the refrigerant, and improve the durability of the compressor.

In this embodiment, sodium oxide (Na
Although activated alumina having a pH of 8.2 containing 3% by weight of O2) was used, the same effect can be obtained if the solid surface of the activated alumina is alkaline.

Further, in this embodiment, the average diameter of the pores is about 8 nm.
However, the average diameter of the pores of the activated alumina is usually 5 to 15 nm, which is sufficiently larger than the molecular diameter of the commonly used refrigerant, and there is no problem.

In this embodiment, the refrigerant R12 having a molecular diameter of about 0.5 nm and the A-type synthetic zeolite having an effective diameter of 0.4 nm were used. However, if a refrigerant composed of a halogenated hydrocarbon compound and a synthetic zeolite are used, an inorganic acid Since a similar problem of crushing synthetic zeolite due to occurs, the effect of the present invention can be expected.

A second embodiment of the present invention will be described below with reference to the drawings. An outline of a refrigeration system using the refrigerant R12 of the present invention will be described with reference to FIG. 4 is a refrigeration system. Reference numeral 11 denotes a compressor, and the refrigerant discharged from the compressor discharge part 13 is condensed in the condenser 14.

Moisture is removed from the condensed refrigerant by the dryer 15. 5m diameter synthetic zeolite in the dryer 15
A desiccant 16 formed in a spherical shape of m is enclosed.

The synthetic zeolite used as the desiccant 16 is an A-type synthetic zeolite having an effective diameter of 0.4 nm that does not adsorb the refrigerant R12 having a molecular diameter of about 0.5 nm.

Reference numeral 17 is an electromagnetic valve using a solenoid, and the refrigerant passes through the capillary tube 18 while being decompressed, and is evaporated by the evaporator 19. Reference numeral 20 is an accumulator that adjusts an appropriate amount of refrigerant.

An acid removing device 5 encloses an adsorbent 6 formed by molding a metal foam having a porosity of 90% by volume, which is made of an alloy of 35% by weight of chromium and 65% by weight of nickel. Here, deterioration of the synthetic zeolite used in the desiccant 16 by removing the inorganic acid contained in the refrigerant,
It prevents crushing.

The refrigerant passes through the check valve 22 and returns from the compressor suction portion 23 to the compressor. By repeating this, cooling is performed.

The characteristics of the metal foam used for the adsorbent 6 are as follows. Hardness about HV300, Pore diameter 500
Since it is a continuous porous body having a diameter of up to 1000 μm and is press-fitted and fixed in the acid removing device 5 without obstructing the flow path of the refrigerant, it has a characteristic that mechanical strength against vibration and the like is higher than that of the activated alumina molded body.

As the composition of the metal foam, a combination of chromium, which is excellent in the chemical adsorption of the inorganic acid, and nickel, which is relatively inert to the inorganic acid, is selected. Since the metal itself corrodes when it chemisorbs an inorganic acid, the chemisorption of various metals was evaluated from the degree of corrosion in an aqueous solution of a high concentration inorganic acid (hydrochloric acid). When the degree of corrosion of iron is 100, nickel, molybdenum, tungsten, cobalt and copper used in general alloy steel are all 20 or less, while chromium is 700 or more.

Chromium is effective against the corrosion of oxygen in the atmosphere by the passivation film of chromium oxide, whereas it is not effective against inorganic acid (hydrochloric acid), and vice versa. The results showed excellent chemisorption of Therefore, chromium is the most suitable material for the metal foam, but when a large amount of inorganic acid (hydrochloric acid) is generated, the whole is corroded, resulting in a decrease in strength. Therefore, the degree of corrosion is 5 and the inorganic acid ( Nickel, which has low activity against hydrochloric acid), is combined.

As described above, according to this embodiment, chromium 3
Porosity 9 composed of alloy of 5% by weight and 65% by weight of nickel
In order to remove water in the refrigerant while maintaining high mechanical strength even when a large amount of inorganic acid is generated, by disposing an acid removal device that encloses an adsorbent made of 0% by volume metal foam. In addition, deterioration and crushing of the synthetic zeolite installed in the refrigeration system can be prevented, and the durability of the compressor can be improved.

In this embodiment, a metal foam containing 35% by weight of chromium and 65% by weight of nickel was used.
Similar effects can be obtained with 0 to 50% by weight of metal foam.

In this embodiment, the pore size is 500 to 1000.
Although a metal foam having a micrometer and a porosity of 90% by volume was used, there is no problem as long as it does not hinder the flow path of the refrigerant.

In this embodiment, the refrigerant R12 having a molecular diameter of about 0.5 nm and the A-type synthetic zeolite having an effective diameter of 0.4 nm were used. However, if a refrigerant composed of a halogenated hydrocarbon compound and a synthetic zeolite are used, an inorganic acid Since a similar problem of crushing synthetic zeolite due to occurs, the effect of the present invention can be expected.

[0046]

As described above, according to the present embodiment, by disposing an acid removing device in which an adsorbent made of activated alumina showing alkalinity is enclosed, polymerization of unsaturated compounds existing in the refrigeration system and Without the effect of adsorption of refrigerant molecules,
It is possible to prevent deterioration and crushing of the synthetic zeolite installed in the refrigeration system to remove water in the refrigerant, and improve the durability of the compressor.

Further, according to this embodiment, chromium is added in an amount of 10 to 10.
By disposing an acid removing device enclosing an adsorbent made of a metal foam containing 50% by weight, water in the refrigerant is removed while maintaining high mechanical strength even when a large amount of inorganic acid is generated. Therefore, it is possible to prevent deterioration and pulverization of the synthetic zeolite installed in the refrigeration system and improve the durability of the compressor.

[Brief description of drawings]

FIG. 1 is a diagram showing a refrigeration system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a refrigeration system according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a refrigeration system in a conventional example.

[Explanation of symbols]

 2 Acid remover 3 Adsorbent 5 Acid remover 6 Adsorbent

Claims (3)

[Claims] 1. A refrigerant comprising a halogenated hydrocarbon compound, a compressor for compressing the refrigerant, a dryer connected to a channel of the refrigerant and containing a desiccant composed of synthetic zeolite, and a channel of the refrigerant. A refrigeration system provided with a connected acid removing device. 2. The refrigerating system according to claim 1, wherein an adsorbent made of alkaline activated alumina is arranged in the flow path of the refrigerant as the acid removing device. 3. The refrigerating system according to claim 1, wherein an adsorbent made of a metal foam containing 10 to 50% by weight of chromium is provided in the refrigerant passage as the acid removing device.